The present invention relates generally to the art of devices for dispensing a viscous liquid, such as liquid soap. More particularly, the invention relates to counter-mounted viscous liquid dispensers of the type which are often utilized in public washrooms and the like.
A variety of counter-mounted soap dispensers have been provided in the prior art. In one conventional arrangement, a dip tube is inserted into a refillable soap reservoir located below the counter. A dispenser fixture, located above the counter, includes an actuation button that is depressed by a user when a quantity of soap is desired. The dip tube includes a pump which is operated when the actuation button is depressed to draw soap from the reservoir. Simultaneously, soap is pushed through a delivery spout of the dispenser fixture, into the user's hand. Check valves are often provided to ensure that soap will flow only toward the delivery spout, and will not undesirably flow back into the reservoir.
Because these arrangements are permanent installations, the pump and/or valves may fail or become clogged over a period of time. In part to overcome this disadvantage, an alternative arrangement was invented whereby the pump and valves are provided as part of a disposable refill cartridge. As shown in U.S. Pat. No. 5,226,566 to Brandenburg, incorporated herein by reference, this arrangement uses a dispenser fixture having an actuator rod that moves when a user depresses an actuation button. The rod engages a pump piston in the refill cartridge to cause liquid soap to be pumped through a delivery tube. The delivery tube extends completely through the delivery spout of the fixture such that the liquid soap does not come into contact with the delivery spout.
While the arrangement of Brandenburg has been effective at overcoming various drawbacks of prior arrangements, further room for improvement exists in the art.